Add new value "spacebar" to Key.backgroundType attribute

Bug: 17318036
Change-Id: Ie84438a6aa3adc14a9db603d0cd4d5e37a55d612
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 009df79..57e7376 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -284,6 +284,7 @@
             <enum name="stickyOff" value="3" />
             <enum name="stickyOn" value="4" />
             <enum name="action" value="5" />
+            <enum name="spacebar" value="6" />
         </attr>
         <!-- The key action flags. -->
         <attr name="keyActionFlags" format="integer">